Heretofore, when a rim was of a split type, and a tubeless tire was to be fitted to the rim made by integrally connecting together the split rim members, a sealing member would be interposed in sealing the tire and rim to maintain the airtightness between them. A groove for inserting the sealing member is required for the wheel rim using such tubeless tire. Such groove has heretofore been shaped by such mechanical operations as cutting, pressing, shaping or casting.
In shaping such groove for inserting the sealing member, in case the diameter is comparatively small as in the wheels of automobiles, there will be no serious problem. But in case a wheel of a large diameter as in autobicycles or motorcycles is of a split rim type and is worked by cutting or the like to adopt a tubeless tire, in order to obtain precision many steps and troubles will be required for manufacture, the operations will be troublesome and complicated, the productivity will be very low, and the cost will be high. Further, in the pressing molding or the like, an extraction gradient will be required in shaping. Therefore, the groove will be tapered and the sealing member will not be seated properly, will therefore require great care in being inserted, will drop in the assembling work, and will not be adaptable to mass-production.